It was the Battle Result tab opening that caused the crash, I think. They had their last unit in the public square, and my army was pressing upon it from both sides, firing missiles. Just as my cavalry charged in from one side, and my Princepes from the other, the game crashed.

Also, I was surprised at just how effective starving them out was. If I play as Rome again, I think I'll do more of that when attacking Northern Italy. Why waste thousands and thousands of mnai raising new armies, when I can spend the money developing infrastructure and economy?

@Andy: I'm pretty satisfied playing on medium, for now. I seem to make it hard enough for myself as it is. :)